This paper presents a Linux virtual server (LVS) based cluster system which is designed to simulate the operation of E-mail service in the real world. For a complete study of the system we build a load generator that is used to perform a series of stress-tests with LVS load-balancing technology. We obtain important results by comparing a series of stresstesting reports. After we take some steps to resolve problems of the system we obtain the expected results, that is, a well-designed system which provides scalable, reliable and highly cost-efficient E-mail service.